/Engine/Plugins/Experimental/Mutable/Source/MutableRuntime/Public/MuR/MutableMath.h
If the boxes don't intersect, at least one size of the returned box will be negative.
[box](API\Plugins\MutableRuntime\MuR\box)< VECTOR > Intersect ( const [box](API\Plugins\MutableRuntime\MuR\box)< VECTOR > & other ) const